Polymer scientia

                          There is nothing called universal rubber              Rubber is a polymer material which finds wide range of applications starting from the gaskets used in your cooking vessels to aero plane tires where you have demanding requirements. Though from an outsider point of view, all the rubber may look similar, but each rubber has its unique properties and should be used for specific applications only. There is nothing called universal rubber which can work for all applications.      Selection of rubber is a science                 The selection of rubber needs the knowledge about the structure and property of rubber, application conditions like temperature, pressure, environment and life cycle of the product and so on. So, selection of rubber is science where you need to deep un...

 In the previous post "Friction material basics: Part 1", we discussed on what is a friction material, its classification based on the composition and finally the current challenges and future scope. Please refer below for the link to "friction material basics: part 1" https://polymerscientia.blogspot.com/2022/06/friction-material-basics-part-1.html In this post "friction material basics: Part 2", we will discuss on the types of binders used in friction material formulation, what are all the advantages of each binder and finally about the current challenges and future scope.  Straight phenolic Novolak resin : Novolak powder resin is widely used in most of the friction material applications like Brake pads, Brake lining, railway brake blocks,clutch facings and other friction products. In the application where the wet mixing is the process, novolak powder resin is used in partially quantity along with the liquid resins. The main advantage of Novolak powder r...

Chemistry of Novolak resin: The word Novolak is derived from two words Novo + lack. Latin word "Novo" refers to novel or new and Swedish word "lack" refers to lacquer. The name Novolak was termed since it had replaced the natural lacquers like shellac and copal resin. Novolak resins are formed by reaction of excess moles of phenol to moles of formaldehyde in the presence of acid catalysts. Generally, the mole ratio (formaldehyde: phenol) of Novolak resins range from 0.5 to 1.0 depends on the demand from the application. Novolaks are stable at room temperature and therefore shelf life of the resin is longer and generally it's six months. But, it can last long if its stored in controlled conditions. In chemistry point of view, in the first step, addition of formaldehyde forms a methylol group in either ortho-para positions of phenol. Under normal conditions, o-p isomer has more possibility compared to p-p' and o-o' bridges. As a next step, methylol group f...

What are Friction materials?  Friction Material is composite material used in brake applications such as brake linings, brake pads and clutch facings used in the automotive vehicles, brake blocks and disc pads used in railways and Sintered brake pads used in aerospace.  The material is called as friction materials because it is exposed to very high frictional forces. Though it's called as friction material by name, it also exposed to wear and lubrication in addition to friction. Please refer the disc brake system assembly and disc pads in the below images                                       Disc pads                                                  Brake linings Image references:  6 Wa...

 At present, there  are many kinds of plastics used for myriad number of applications starting from FMCG to aerospace industries which has a significant impact on our daily lives. Generally, Plastics are classified into two major types according to their thermal behaviour. Thermoplastics : Plastics materials which can melt upon heating and forms the required shape. If the material is heated , it can melt and form into different shapes again. Thermosetting plastics : Plastics materials which can melt upon heating and forms the required shape. If the material is heated again, it cannot melt again since the material is crosslinked / cured. The topic of interest for us is thermosetting plastics and there are various types of thermosetting plastics used commercially because of its unique properties. Phenol Formaldehyde Resins (PFR) is the oldest plastic with the history of more than a century. After World War II, many kinds of plastics were developed and commercialized succe...